changed regex for backup_dir (allow empty backup-dir to disable backups)

Florian Schaal

2016-03-17 93e7c2d51119be25b34fec4b2eb5771f40cf7d31

1
ALTER TABLE `shell_user` CHANGE `ssh_rsa` `ssh_rsa` TEXT CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL;